Wide range AC/DC converter circuit

Abstract

An electric circuit for use with an AC power source includes a diode electrically connected to a line input from the AC power source, a transistor having a gate, a drain, and a source, wherein the drain is electrically connected to the diode, a zener diode electrically connected between the gate and the source of the transistor, a resistor electrically connected between the drain of the transistor and a neutral input from the AC power source, and a capacitor electrically connected in parallel with the resistor.

What is claimed is: 
     
       1. An electric circuit for use with an AC power source, the electric circuit comprising:
 a diode electrically connected to a line input from the AC power source; 
 a transistor having a gate, a drain, and a source, wherein the drain is electrically connected to the diode; 
 a zener diode electrically connected between the gate and the source of the transistor and having a cathode connected to the gate; 
 a resistor electrically connected between the source of the transistor and a neutral input from the AC power source; 
 a capacitor electrically connected in parallel with the resistor; and 
 at least two second zener diodes electrically connected between the gate and the neutral input and having cathodes at least one of the at least two second zener diodes having a cathode connected to the gate, 
 wherein a voltage across the resistor is a direct current voltage having a value equal to a sum of breakdown voltages of the second zener diodes minus a breakdown voltage of the zener diode. 
 
     
     
       2. The electric circuit of  claim 1 , wherein a cathode of the zener diode is electrically connected to the gate and an anode of the zener diode is electrically connected to the capacitor and the resistor. 
     
     
       3. The electric circuit of  claim 1 , wherein the at least two second zener diodes are two second zener diodes electrically connected in series between the gate and the neutral input. 
     
     
       4. The electric circuit of  claim 3 , wherein a breakdown voltage of the zener diode is 12V. 
     
     
       5. The electric circuit of  claim 3 , wherein a sum of breakdown voltages of the second zener diodes is 191V. 
     
     
       6. The electric circuit of  claim 1 , further comprising:
 a second resistor electrically connected between the diode and the gate of the transistor. 
 
     
     
       7. The electric circuit of  claim 6 , wherein a resistance of the resistor is equal to a resistance of the second resistor. 
     
     
       8. The electric circuit of  claim 1 , further comprising:
 a metal oxide varistor (MOV) electrically connected between the line and the neutral; and 
 a third resistor electrically connected between a cathode of the diode and the MOV. 
 
     
     
       9. The electric circuit of  claim 1 , wherein the transistor is a metal oxide semiconductor field effect transistor (MOSFET). 
     
     
       10. The electric circuit of  claim 1 , wherein the capacitor has a capacitance of 4.7 uF. 
     
     
       11. The electric circuit of  claim 1 , wherein the transistor is structured to turn on when an input voltage between the line input and neutral input begins a positive half-cycle. 
     
     
       12. The electric circuit of  claim 1 , wherein a voltage across the resistor is 180V when an input voltage between the line and neutral is 365 Vrms. 
     
     
       13. The electric circuit of  claim 1 , wherein there is no isolation between the AC power source and the line and neutral inputs.